## Cryptology ePrint Archive: Report 2021/1483

A Practical Forward-Secure DualRing

Nan Li and Yingjiu Li and Atsuko Miyaji and Yangguang Tian and Tsz Hon Yuen

Abstract: Ring signature allows a signer to generate a signature on behalf of a set of public keys, while a verifier can verify the signature without identifying who the actual signer is. In Crypto 2021, Yuen et al. proposed a new type of ring signature scheme called DualRing. However, it lacks forward security. The security of DualRing cannot be guaranteed if the signer's secret key is compromised. In this work, we introduce forward-secure DualRing. The singer can periodically update his secret key using our proposed split-and-combine" method to mitigate the security risks caused by the leakage of secret keys. We present a practical scheme based on the discrete logarithm assumption. We show a detailed evaluation to validate its practicality.

Category / Keywords: public-key cryptography / DualRing, Forward Security, Practical Scheme